On Sep 9, 8:26 pm, djh <halitsk...@att.net> wrote:> I've programmed and desk-checked the custom heteroscedastic test in> Perl.>> By checking each step of the calculation against the corresponding> step in Excel 2010, I have verified that this PERL version is working> correctly.>> However:>> 1) the PERL "dist" function only accepts integer "ft's" (degrees of> freedom);>> 2) it reports a one-tailed p out to 6 decimal places.>> So, for:>> t = 1.75392432472924> ft = 1545.45548783244>> I get the following p (after multiplying the PERL one-tailed p by 2):>> p (two-tailed) = 0.079642>> which matches the Excel 2010 two-tailed p as far as it goes out.>> (I get this p whether I submit with 1545 or 1546 ... I do both in the> code just to check for a difference, though there won't often be one,> I don't think.)

Use the lower value (e.g., 1545, not 1546).

A related question: Does any of your software have an "IncompleteBeta" function,

I[x,a,b] = integral{t = 0..x} t^(a-1) (1-t)^(b-1),

were 0 <= x <= 1 and a,b > 0? Or (even better) a "regularized" or"normalized" incomplete beta, that gives I[x,a,b]/B[a,b], whereB[a,b] = I[1,a,b] is the usual Beta function? If so then the t and Fprobs can be obtained from I[x,a,b].